Spectacles.

A modern pair of prescription reading glasses

Modern glasses are typically supported by pads on the bridge of the nose and by temple arms (sides) placed over the ears. CR-39 lenses are the most common plastic lenses due to their low weight, high scratch resistance, low dispersion, and low transparency to ultraviolet and infrared radiation.^{[citation needed]} Polycarbonate and Trivex lenses are the lightest and most shatter-resistant, making them the best for impact protection.^[1]

An unpopular aspect of glasses is their inconvenience. Though modern frames can be both lightweight and flexible, and new lens materials and optical coatings are resistant to breakage or scratching, glasses can still cause problems during rigorous sports. Visibility can be significantly reduced by becoming greasy, trapping vapour when eating hot food, swimming, walking in rain or rapid temperature changes (such as walking into a warm building from cold temperatures outside). Scraping, fracturing, or breakage of the lenses require time-consuming and costly professional repair.

Invention of eyeglasses

The 'Glasses Apostle' by Conrad von Soest (1403)

The first eyeglasses were made in Italy at about 1286, according to a sermon delivered on February 23, 1306 

The American scientist Benjamin Franklin, who suffered from both myopia and presbyopia, invented bifocals.

Woman wearing designer sunglasses.

Nobel Prize in Medicine and Physiology..1999

The Nobel Prize in Physiology or Medicine 1999

The Nobel Assembly at Karolinska Institutet in Stockholm, Sweden, has awarded the Nobel Prize in Physiology or Medicine for 1999 to Günter Blobel, for the discovery that "proteins have intrinsic signals that govern their transport and localization in the cell."

Günter Blobel, born in 1936, works at the Laboratory of Cell Biology, The Rockefeller University, New York

All living organisms are made up of cells. The eukaryotic cell contains a number of different types of organelles each of which is surrounded by a tightly sealed membrane. Future applications In the near future the entire human genome will be mapped. As a result one can also deduce the structure and topogenic signals of the proteins. This knowledge will increase our understanding of processes leading to disease and can be used to develop new therapeutic strategies. Already today drugs are produced in the form of proteins, e.g. insulin, growth hormone, erythropoetin and interferon. Usually bacteria are used for the production of the drug, but in order to be functional certain human proteins need to be synthesized in more complex cells, such as yeast cells. With the help of gene technology the genes of the desired proteins are provided with sequences coding for transport signals. The cells with the modified genes can then be efficiently used as protein factories. Increased knowledge about the process by which proteins are being directed to different parts of the cell also makes it possible to construct new drugs that are targeted to a particular organelle to correct a specific defect. The ability to reprogram cells in a specific way will also be important for future cell and gene therapy. Fig. 1. "The signal hypothesis". Proteins which are to be exported out of the cell are synthesized by ribosomes, associated with the endoplasmic reticulum. The genetic information from DNA is transferred via messenger RNA (mRNA). This information determines how the amino acids build up the proteins. First, a signal peptide is formed as a part of the protein. With the help of binding proteins, the signal peptide directs the ribosome to a channel in the endoplasmic reticulum. The growing protein chain penetrates the channel, the signal peptide is cleaved, and the completed protein is released into the lumen of the endoplasmic reticulum. The protein is subsequently transported out of the cell.